mkvpeek

const 
const source: Source
source = 
function blobSource(blob: Blob, options?: BlobOptions): Source
A source over a Blob, such as a picked File, read as on a local disk.
WARN: a file on a network share wants trip: "mount", or a walk reads nearly all of it over the link.
blobSource(
const file: File
file);
await using 
await using container: Container
container = await 
function openContainer(target: Target, options?: Abortable): Promise<Container>
Opens a container for its tracks' frames, and keeps the target open until close.
It reads what peekTracks reads with info,
and throws a refusal at the open or at a read as a RefusalError.
openContainer(
const source: Source
source);

const 
const files: SubtitleFile[]
files = await 
function subtitleFiles(container: Container, options?: SubtitleOptions): Promise<SubtitleFile[]>
Writes out every track of container.tracks whose format formats names and that readable answers true for.
It writes nothing where that read is refused.
subtitleFiles(
await using container: Container
container);